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Port 609 (npmp-trap)

IANA assigns port 609 to npmp-trap.

Well-known (system) port, 0-1023 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
npmp-trap TCP npmp-trap - -
npmp-trap UDP npmp-trap - -

Check what is listening on port 609

Linux: is anything listening on TCP 609?
sudo ss -tlnp 'sport = :609'
Linux: UDP 609
sudo ss -ulnp 'sport = :609'
Linux / macOS: which process owns the port
sudo lsof -nP -i :609
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':609 '
Windows (Command Prompt)
netstat -ano | findstr :609
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 609 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 609
From Windows
Test-NetConnection HOST -Port 609
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 609

Block port 609 in the firewall

ufw
sudo ufw deny 609/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 609 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 609 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 609' -Direction Inbound -Protocol TCP -LocalPort 609 -Action Block
ufw
sudo ufw deny 609/udp
iptables
sudo iptables -A INPUT -p udp --dport 609 -j DROP
nftables
sudo nft add rule inet filter input udp dport 609 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 609' -Direction Inbound -Protocol UDP -LocalPort 609 -Action Block

Related ports

607nqs608sift-uft610npmp-local611npmp-gui

All port numbers · Open port checker
Assignment data: IANA port number registry (public domain), retrieved 2026-11-10.